[markhellewell]

On OpenBSD the integration with physical devices is done via builtin software. I run a stratum 1 OpenNTPD server on OpenBSD, with a GPS attached via nmea [1]. The GPS data shows up via the sensors framework, which OpenNTPD interfaces with [2].

[1] http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man4/...

[2] http://openbsd.id/papers/radio-clocks-asiabsdcon07.pdf

[gonzo]

It's interesting how the author of the paper (and work) gets PPS sampling wrong.